The Colts left Baltimore in 1984.
Sick of Baltimore
The Colts relocated from Baltimore to Indianapolis in 1984.
The Baltimore Ravens have always existed as the Baltimore Ravens. Originally, the franchise was the Cleveland Browns; however, then owner Art Modell agreed to leave the Browns name and legacy in Cleveland after the NFL promised the City of Cleveland another team.
Art Modell, the Cleveland Browns owner, threatened to leave town for Baltimore. Later on he did, and the Ravens got new uniforms, logos, stadiums, but still kept the players and coaches.
The Ravens were originally the Cleveland Browns before owner Art Modell moved the team to Baltimore. As part of legal agreement, Modell agreed to leave the Browns history and records in Cleveland, and the Ravens started as a new football team within the NFL.
The Colts relocated from Baltimore in 1984, and began their stay in Indianapolis winning 90 of 228 games through the 1997 season, including 5 playoff games.
Yes, Marvin Harrison did leave the colts.
15 trucks from Mayflower went to the Colts' training complex in Maryland around 2 AM on March 29, 1984 and workers began loading all of the team's belongings on them. By mid morning the trucks were gone and so were the Colts.
The Ravens came into existence when Cleveland Browns owner Art Modell signed an agreement with City of Baltimore and the Maryland Stadium Authority to move the franchise to Baltimore for the 1996 season. Following several legal disputes, Modell agreed to leave the Browns name and history in Cleveland, and start fresh in Baltimore. We're glad he did; "Baltimore Browns" just never had quite a great ring to it, their team colors are lame.